Public bug reported: Upstream's Spectre v1 mitigation prevents speculation on a user controlled pointer. This part of the Spectre v1 patchset was never backported to 4.4 (for unknown reasons) so Xenial is lacking it as well. All the other stable upstream kernels include it, so add it to Xenial. Specifically, the following patches are needed:
c7f631cb07e7 x86/get_user: Use pointer masking to limit speculation 304ec1b05031 x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec b5c4ae4f3532 x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end} b3bbfb3fb5d2 x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec ** Affects: linux (Ubuntu) Importance: Undecided Status: Incomplete -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1775137 Title: Prevent speculation on user controlled pointer Status in linux package in Ubuntu: Incomplete Bug description: Upstream's Spectre v1 mitigation prevents speculation on a user controlled pointer. This part of the Spectre v1 patchset was never backported to 4.4 (for unknown reasons) so Xenial is lacking it as well. All the other stable upstream kernels include it, so add it to Xenial. Specifically, the following patches are needed: c7f631cb07e7 x86/get_user: Use pointer masking to limit speculation 304ec1b05031 x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec b5c4ae4f3532 x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end} b3bbfb3fb5d2 x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1775137/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp